Endocrine and nutritional influences on the general metabolic reaction to severe trauma or hemorrhagic shock constitute major areas of potential therapeutic intervention. Conservation of protein dependent systems, particularly those responsible for respiration, cardiovascular adequacy and immune reaction to pathogenic invasion, will be likely to decrease morbidity and mortality and promote rapid recovery after major injury. Our laboratory is involved in the investigation of the metabolic derangements experienced after trauma, and the mechanisms responsible for their inception. Emphasis will be directed to the study of circadian rhythms of cortisol in surgical patients. The eventual alterations in the periodicity of plasma cortisol levels will be correlated with the degree of trauma and parameters of post-operative evolution. This information will provide an important insight into the genesis of the post-traumatic metabolic and endocrine disturbances that occur in surgical patients. This knowledge will eventually be of prognostic and therapeutic value in the management of severely traumatized patients. In the area of post-shock and post-trauma metabolism, our efforts will be directed towards the exploration of a Rhesus monkey model which will enable us to assess hepatic and hind limb metabolite handling. The objectives will be to determine triggering factors responsible for protein hypercatabolism and hepatic gluconeogenesis and the effects of different therapeutic agents and solutions on these phenomena.